nōsce tē

Meaning

1. know thyself
   [...] illa Pythicis oraculis adscripta : nosce te. Quid est homo?c. 4 BCE – 65 CE, Seneca Minor, Dialogus ad Marciam de consolatione 11.3.1-2

Origins

Calque of Ancient Greek γνῶθι σεαυτόν (gnôthi seautón), one of the Delphic maxims. The Greek contains a reflexive pronoun, but in Classical Latin there had been no dedicated reflexive form of tē (but only emphatic forms such as tētē, which are not necessarily reflexive), and accordingly the Greek dedicated reflexive form σεαυτόν (seautón) was rendered with a simple tē in Latin, which covers reflexive uses. The Classically unattested translations include emphatic forms of the pronoun used as pseudo-reflexives in an attempt to match the compound nature of σεαυτόν (seautón), or genuine Late Latin reflexive formations.